In poultry processing plants today, where poultry is prepared for sale as fresh produce, birds are killed, eviscerated and chilled prior to being bagged for distribution and sale. The birds are chilled to enhance moisture retention so that they will stay moist when cooked and so that the skin will not tend to separate from the meat for enhanced eatability and cosmetic appearance. The chilling is typically done by dropping eviscerated birds into a tank of cold water for a period of time sufficient to lower the body temperature from some 90.degree. to 98.degree. F. following evisceration, to some 35.degree. to 40.degree. F., depending on their size.
More recently, birds have been chilled to a much lower body temperature, just above their freezing temperature, for the same reasons, i.e. for better moisture retention and skin adherence as well as for improved coloration and shelf life. This has been done by what is known as a crystal pack operation wherein birds are passed through a refrigerated room suspended from shackles following their emergence from the chiller. Within the crystal pack room the birds are subjected to a flow of cold air being blown at high velocities for a period of almost an hour. This operation serves to lower the body temperature of the bird from some 35.degree. to 40.degree. F. following emergence from the chiller to approximately 29.degree. F. with the skin of the bird being approximately at 281/2.degree. F. At this temperature the birds are very close to but are not actually frozen although moisture on the skin of the bird will have crystallized. As previously stated, this crystal pack operation serves to enhance shelf life of the birds and also to enhance the birds cosmetically. Particularly, this form of chilling renders the bird more yellowish due to the fast rate of heat removal. Again, better moisture retention is also achieved as is skin to meat adherence.
Though the just described crystal pack operation has provided the just described advantages it is not done so without creating certain disadvantages of its own. Probably the most important disadvantage associated with crystal pack operations has to do with the difficulty of modeling or shaping the birds for insertion into a packaging bag for shipment and distribution. Prior to the use of the crystal pack operation the temperature of the birds was only reduced to some 35.degree. to 40.degree. F. At this temperature the birds, which are typically young broilers of some seven to eight weeks of age, are still sufficiently pliable or flexible so as to enable workers to form or truss them into a compacted configuration which sometimes in the industry is referred to as a "butterball" shape. In this configuration the thighs of the birds are raised up against the bird breast with wings usually tucked in between the thighs. With the use of the crystal pack operation, however, the temperature of the birds has been reduced over a substantial period of time almost to a body frozen temperature prior to bagging. This causes the birds to be stiff due to their cold body temperature and the effects of rigor mortis. It thus is difficult to shape or model the birds into the compact, butterball position during the packaging operation. This is particularly true in view of the fact that the birds are suspended invertedly from shackles in a stretched-out position as they are conveyed through the crystal pack room. This stretched out position is, of course, just the opposite of the compacted, butterball position. In addition, in the invertedly suspended position the birds take different orientations such, for example, with one or both wings draped downwardly or at some inclined angle. This leads to variations in time required to bag the birds which are being delivered to the packaging station at regular intervals. The inverted conveying position also leads to weepage during crystal pack operation wherein moisture may be lost from the surface of the skin.
Accordingly, it is seen that a need remains for overcoming the just described problems associated with the use of crystal pack operations in the processing of poultry for sale as fresh produce. It is to the provision of a solution to the just described problem that the present invention is primarily directed.